Since the 1.0d patch for Rise of Rome, the . key can be used to cycle through any idle villagers. This is extremely useful in reducing idle time and maximising efficiency.
Idle villagers are usually caused by a lack of prioritization of tasks or simply forgetfulness and distraction. They may also result from a player completing a task too quickly, such as 20 villagers building a tower or storage pit before stone mining. In this case, players very often leave the villagers idle for several minutes.
Grouping is a method of preventing idle villagers or units. For example, when ten villagers are dedicated as stone miners, they must build a storage pit first. A player can group these villagers by pressing ctrl + number, so that they can instantly locate groups of villagers to perform the next task.
Another method is to have a dedicated builder and the rest as miners or gatherers. For example, when 10 villagers are going to mine stone, one villager can build a storage pit, while the rest are sent to mine stone. If the miners finish before the builder, then use two builders.
A player should never have groups of idle villagers such as in the picture on this page. They can always do basic resource gathering, such as pick berries, which are always near town centers. This is very common among high expert players.
Although idle legions are not as big of a fuss as idle villagers, it is still a strain on efficient and strong play. Much of the game play is focused on one's army, so there aren't many techniques to reduce it. Most of the strategy and tactics for legions can be found in the Army Control page.